题目地址:Reverse Integer
题目简介:给出一个数字得到从后往前输出的结果,如果大于所需要的结果,那么将输出0;
Given a 32-bit signed integer, reverse digits of an integer.
Example 1:
Input: 123
Output: 321
Example 2:
Input: -123
Output: -321
Example 3:
Input: 120
Output: 21
Note:
Assume we are dealing with an environment which could only store integers within the 32-bit signed integer range: [−231, 231 − 1]. For the purpose of this problem, assume that your function returns 0 when the reversed integer overflows.
题目解答:
C++版:
class Solution {
public:
int reverse(int x) {
double ans = 0;
double positive = 2147483647;
double negative = -2147483648;
if (x < 0)
{
if (x == negative)
return 0;
int temp = -1 * x;
while (temp >= 10)
{
ans += (temp % 10);
temp /= 10;
ans *= 10;
}
ans += temp;
ans *= -1;
if (ans < negative)
return 0;
else
return (int)ans;
}
else
{
while (x >= 10)
{
ans += (x % 10);
x /= 10;
ans *= 10;
}
ans += x;
if (ans > positive)
return 0;
else
return (int)ans;
}
}
};